Transport and storage of Helicobacter pylori from gastric mucosal biopsies and clinical isolates

Presence of multivessel coronary artery disease (MVD) identifies a high risk subgroup after acute myocardial infarction (AMI). Dobutamine stress echocardiography (DSE) has recently emerged as a promising non invasive test to detect the presence and extent of coronary artery disease. Forty six consecutive patients (38 males, 8 females; mean age 48.6 +/- 10.4 years) of Q-wave acute myocardial infarction were subjected to submaximal treadmill test (TMT) and dobutamine stress echocardiography to see their ability to predict multivessel coronary artery disease as detected by coronary angiography before hospital discharge. Dobutamine infusion was started at 5 micrograms/kg/min to a maximum of 40 micrograms/kg/min, to achieve 70 percent of the age predicted heart rate. Appearance of new regional wall motion abnormality was interpreted as positive DSE for MVD. Mean peak infusion dose of dobutamine used in the study was 28.56 +/- 5.67 micrograms/kg/min. In none of the patients, the test had to be terminated due to side effects. The sensitivity and specificity of DSE to predict MVD was 80 percent and 93.7 percent, respectively as compared to 45 percent and 86 percent for submaximal TMT. Thus, DSE in patients of AMI before hospital discharge is a safe procedure with fairly accurate prediction of multivessel coronary artery disease.     

A case report of ulcerative colitis complicated with protein losing enteropathy and colon cancer in a young female

AIMS: To assess the ability of dobutamine echocardiography to detect multivessel coronary artery disease and to determine predictive factors for multivessel disease with or without beta-blockers. PATIENTS AND METHODS: A total of 101 patients underwent dobutamine stress echocardiography and coronary angiography (evaluation of chest pain 76, extent of coronary disease after myocardial infarction 19, other indications 6). RESULTS: Ten patients in whom the test was prematurely terminated were excluded. Out of 91 patients who underwent dobutamine echocardiography, 54 patients had multivessel disease (sensitivity of dobutamine test 93%, specificity 46%). Heart rate at the maximum dose of dobutamine or atropine was 88 +/- 21 beats/min for multivessel diseases and 104 +/- 21 beats/min without multivessel disease (p < 0.001). A cut-off value < 94 beats/min discriminated patients at risk for multivessel disease. After adjusting for treatment with beta-blockers, heart rate < 94 beats/min, ECG signs of ischemia, and abnormalities on baseline echocardiogram with remote asynergies during dobutamine testing were independent predictors of multivessel disease in the multivariate analysis (probability > 90% when at least two factors were present). CONCLUSION: A heart rate < 94 beats/min at peak dose of dobutamine or after atropine, ECG signs of ischemia, and the presence of abnormalities on echocardiogram at rest with remote asynergies during dobutamine stress testing were independent predictive factors of multivessel coronary artery disease.     

Echocardiography with dobutamine in hypertensive patients with chest pain

INTRODUCTION: The exercise stress test shows limited diagnostic accuracy for the detection of coronary artery disease in hypertensive patients. Echocardiography with dobutamine is a useful tool in the assessment of coronary artery disease. PURPOSE: Our purpose has been to compare dobutamine stress echocardiography and exercise stress test for diagnosing coronary disease in hypertensive patients. MATERIAL AND METHODS: Dobutamine stress echocardiography (administered up to 40 micrograms/kg/min, and atropine when necessary), exercise stress test and coronary arteriography were performed on 74 hypertensive patients with chest pain and no previous history of coronary artery disease. RESULTS: Forty-eight (65%) patients underwent a diagnostic exercise stress test and 66 (89%) a diagnostic dobutamine stress echocardiography. Coronary artery disease (> or = 70% stenosis in, at least, one major vessel) was demonstrated in 28 (58%) patients who underwent a diagnostic exercise stress test, and in 39 (59%) patients who completed a dobutamine stress echocardiography. Sensitivity for exercise stress test was 82%, and 79% for dobutamine stress echocardiography (p = NS). Specificity was higher for dobutamine stress echocardiography (100% vs 60%; p < 0.005). CONCLUSIONS: Dobutamine stress echocardiography has high sensitivity and specificity for the detection of coronary artery disease in hypertensive patients. Dobutamine stress echocardiography has higher feasibility and specificity than exercise stress test in this group of patients.     

Ischemic heart disease and postoperative mortality in major vascular surgery. An up-to-date diagnostic approach

BACKGROUND: The aim of this study is to evaluate the efficacy the dobutamine stress echocardiography in predicting the perioperative cardiac risk of patients undergoing major vascular surgery. METHODS: Seventy-seven consecutive and not selected patients, undergoing a surgical treatment requiring aortic cross clamping, were assessed also with a transthoracic dobutamine stress echocardiography. With electrocardiographic and echocardiographic monitoring ventricular ischemia or wall motion abnormalities, 5 micrograms/kg per min of chlorhydrate dobutamine for 5 minutes were infused, followed by other 10 micrograms/kg per min increased up to 40 micrograms/kg per min. During the last 4 minutes 0.25 mg of atropin were infused increasingly up to 1 mg. RESULTS: Of all these patients, 26 had a stress ischemia but only 4 cases underwent a coronary angiography and only 2 of these underwent a preventive myocardial revascularization. Due to poor cardiac conditions pointed out with the dobutamine stress, 3 patients were not treated surgically. With an aggressive intra- and perioperative monitoring 73 patients underwent a surgical treatment: they were 28 aorto-bifemoral, 3 aorto-aortic grafts, 1 aorto-bisiliac thoraco-abdominal interposition graft, and 20 aorto-bifemoral, 4 aorto-femoral, 1 aorto-aortic thoraco-abdominal, 1 aorto-renal by-pass and 7 aorto-iliac-femoral thromboendoarterectomies. In the postoperative period 4 cardiac ischemic complications and 2 deaths (2.5%) were observed. CONCLUSIONS: According to our personal opinion, stress echocardiography can be considered a test with a excellent feasibility and safety rate, not expensive and with a good reproducibility and reliability. It allowed to predict the cardiac risk in our patients suggesting not only the surgical but also the anesthesiologic and the perioperative therapeutic management.     

Long-term prognostic significance of dobutamine echocardiography in patients with suspected coronary artery disease: results of a 5-year follow-up study

OBJECTIVES:This study sought to assess the long-term prognostic utility of dobutamine stress echocardiography in predicting fatal and nonfatal cardiac events. BACKGROUND: Although dobutamine stress echocardiography has improved sensitivity and specificity for detection of coronary artery disease, little is known of its predictive value for long-term cardiac events. Therefore, we followed up 120 consecutive patients who underwent dobutamine echocardiography for suspected coronary disease from March 1989 to August 1991. METHODS: All patients presenting for coronary angiography for chest pain were eligible for recruitment. Follow-up was 100% complete at 5 years (range 3.0 to 6.1). Cardiac events were defined as cardiac death or nonfatal myocardial infarction or the need for coronary revascularization (coronary angioplasty or bypass surgery). RESULTS: Positive (n = 78) and negative (n = 42) dobutamine test groups differed in their rates of coronary artery bypass graft surgery (37.2% vs. 9.5%, p < 0.001, respectively) and mortality. Of 26 total deaths, 22 occurred in the group with positive dobutamine test results (28% vs. 9.5%, p < 0.018); all 7 cardiac deaths occurred in this group as well (9% vs. 0%, p < 0.045). By multivariate regression analysis, positive results on dobutamine echocardiography remained independently predictive of future cardiac death after left ventricular ejection fraction and other clinical variables were accounted for. CONCLUSIONS: A positive finding on dobutamine echocardiography is an independent predictor of long-term cardiac mortality, whereas a negative finding confers a significantly reduced likelihood of cardiac death as much as 5 years from initial testing. We conclude that dobutamine stress echocardiography can be used to predict which patients with suspected coronary artery disease are at low risk for cardiac death and do not require concurrent nuclear or invasive testing.     

Primary rhabdomyosarcoma of the brain: observations on a case with clinical and radiological evidence of cure

BACKGROUND: After heart transplantation, accelerated coronary vasculopathy is a major factor that limits long-term survival and is usually detected by serial coronary angiography. The aim of this study was to determine whether dobutamine stress echocardiography could accurately identify the progression of cardiac allograft vasculopathy. METHODS: Two sequential controls by dobutamine stress echocardiography were performed at an 18-month interval in 37 heart transplant recipients at the time of their routine coronary angiography. The first control (control 1) occurred 37+/-20 months after transplantation, and the second control (control 2) occurred after 56+/-21 months. Standard echocardiographic views were acquired at baseline and at incremental dobutamine infusion levels. Regional wall motion score was calculated in a 16-segment model, and each segment was graded from 1 (normal) to 4 (dyskinesia). Visual and quantitative coronary angiographic analysis were used to assess the severity of the coronary vasculopathy. RESULTS: The incidence of coronary vasculopathy increased from 46% (17/37 patients, four of whom had stenoses > 50%) at control 1 fo 70% (26/37 patients, six of whom had stenoses > 50%) at control 2. Progression of coronary vasculopathy was diagnosed by coronary angiography in 25 patients (new abnormalities in 19 and worsening of previous abnormalities in 6). Dobutamine stress echocardiography correctly identified the progression of vasculopathy in 21 of these 25 patients (84%) with new abnormalities in 17 and worsening in four. In the four remaining patients with evidence of progression of vasculopathy on coronary angiography, the result of dobutamine stress echocardiography was abnormal in three patients and normal in only one. Therefore dobutamine stress echocardiography results were abnormal in 12 patients at control 1 (sensitivity: 65%, specificity: 95%) and in 27 at control 2 (92% sensitivity, 73% specificity). CONCLUSION: Dobutamine stress echocardiography is a sensitive, noninvasive method to diagnose the progression of allograft vasculopathy, and a negative test result is a strong predictor of absence of allograft coronary vasculopathy. Therefore serial routine coronary angiography may be deferred when dobutamine stress echocardiography results are normal.     

Combined low dose dipyridamole-dobutamine stress echocardiography to identify myocardial viability

OBJECTIVES: We sought to evaluate the effects of combined administration of infra-low dose dipyridamole and low dose dobutamine on assessment of myocardial viability. BACKGROUND: Low dose pharmacologic stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for the recognition of myocardial viability. METHODS: Thirty-four patients with rest wall motion dyssynergy by two-dimensional echocardiography and with angiographically proved coronary artery disease underwent in combination with two-dimensional echocardiographic monitoring: 1) low dose (5 to 10 microgram/kg per min over 3 min) dobutamine infusion; 2) infra-low dose (0.28 mg/kg over 4 min) dipyridamole infusion; 3) combination of infra-low dose dipyridamole infusion immediately followed by low dose dobutamine infusion (combined dipyridamole-dobutamine). RESULTS: Follow-up rest echocardiography was available in 30 patients. After revascularization, 82 segments showed a contractile improvement of > or = 1 grade, whereas 63 segments remained unchanged. The sensitivity of dobutamine, dipyridamole and combined dipyridamole-dobutamine for predicting recovery was 72% (95% confidence interval [CI] 60.9% to 81.3%), 67% (CI 55.8% to 77%) and 94% (CI 86.3% to 97.9%), respectively. The specificity of dipyridamole, dobutamine and combined dipyridamole-dobutamine was 95% (CI 86.7% to 99%), 92% (CI 82.4% to 97.3%) and 89% (CI 78.4% to 95.4%), respectively. The accuracy of the dobutamine, dipyridamole and combined dipyridamole-dobutamine test was 80%, 79% and 92%, respectively (combined dipyridamole-dobutamine vs. dobutamine, p < 0.05; combined dipyridamole-dobutamine vs. dipyridamole, p < 0.01). CONCLUSIONS: Infra-low dose dipyridamole added to low dose dobutamine recruits an inotropic reserve in asynergic segments that were nonresponders after either dobutamine or dipyridamole alone and destined to recover after revascularization.     

Usefulness of isometric hand grip exercise in detecting coronary artery disease during dobutamine atropine stress echocardiography in patients with either stable angina pectoris or another type of positive stress test

Dobutamine atropine stress echocardiography (DASE) detects coronary artery disease (CAD) by increasing myocardial oxygen demand causing ischemia. The sensitivity of the test for detection of CAD is reduced in patients with submaximal stress. We hypothesized that increasing cardiac work load by adding isometric exercise would improve the detection of ischemia during DASE. We studied 31 patients, mean age 57+/-11 years, with angiographically documented CAD. Patients underwent DASE using incremental dobutamine doses from 5 to 40 microg/kg/min, followed by atropine if peak heart rate was <85% of predicted maximal. Hand grip was then performed for 2 minutes at 33% of maximal voluntary contraction, while dobutamine infusion was maintained at the peak dose. The addition of hand grip during dobutamine stress was associated with a significant increase in systolic blood pressure (143+/-21 vs 164+/-24 mm Hg, p = 0.001) and left ventricular end-systolic circumferential wall stress (72+/-30 x 10(3) dynes/cm2 vs 132+/-34 x 10(3) dynes/cm2, p = 0.004). Wall motion score index increased from 1.0 at rest to 1.15+/-0.18 with dobutamine (p = 0.0004 vs rest), and increased further to 1.29+/-0.22 with the addition of hand grip (p = 0.004 vs dobutamine). Ischemia was detected in 19 patients (62%) with dobutamine-atropine stress alone and in 25 (83%) after the addition of hand grip (p <0.05). The addition of hand grip during DASE is feasible, and improves the detection of myocardial ischemia.     

Improved specificity of transesophageal dobutamine stress echocardiography compared to standard tests for evaluation of coronary artery disease in women presenting with chest pain

The detection of coronary artery disease (CAD) by noninvasive methods has been hindered in women by the high rate of false-positive results. To determine the feasibility and accuracy of transesophageal dobutamine stress echocardiography for identification of CAD in women, we studied 84 patients (age 51 +/- 11 years) who underwent symptom-limited exercise treadmill testing, exercise thallium-201 scintigraphy, and coronary angiography for evaluation of anginal chest pain. Of the 84 patients, 62 had normal coronary arteries or nonsignificant coronary lesions, and 22 had significant stenosis of > or = 1 major coronary artery. During treadmill exercise, repolarization changes were observed in 16 of 21 patients with CAD and in 19 of 60 patients with normal coronary arteries. With thallium scintigraphy, a reversible defect was observed in 19 of 22 patients with CAD and in 12 of 60 patients with normal coronary arteries. Regional wall motion abnormalities during dobutamine infusion developed in 18 of 22 patients with CAD and in none of the 62 patients with normal coronary arteries. All 3 tests had similar sensitivity for detection of CAD (76% for exercise treadmill test, 86% for thallium scintigraphy, and 82% for transesophageal dobutamine stress echocardiography). However, transesophageal dobutamine stress echocardiography had significantly higher specificity than the other 2 tests (100% vs 68% for exercise treadmill test and 80% for thallium scintigraphy; p = 0.0001). Thus, transesophageal dobutamine stress echocardiography is accurate for evaluation of CAD among women presenting with chest pain; its use should be considered when more conventional tests are equivocal or technically suboptimal.     

Assessment of myocardial viability: Dobutamine echocardiography and thallium-201 single-photon emission computed tomographic imaging predict the postoperative improvement of left ventricular function after bypass surgery

The aim of this study was to evaluate the usefulness of dobutamine echocardiography and quantitative thallium-201 single photon emission computed tomography myocardial scintigraphy with reinjection in the detection of viable myocardium in patients with coronary artery disease and reduced left ventricular function, which will improve after aortocoronary bypass surgery. Forty-eight patients (47 men, aged 61 +/- 6 years) with angiographically documented reduced left ventricular function (ejection fraction 35 +/- 14, 63% with chronic transmural myocardial infarction) were examined by dobutamine two-dimensional echocardiography (before and during low dosage), 201Tl, and gated radionuclide ventriculography before and 3 +/- 2 months after aortocoronary bypass surgery. Four of 55 areas classified viable before operation were revascularized inadequately and discarded. Global left ventricular ejection fraction at rest rose from 35% +/- 14% before operation to 40% +/- 13% (p < 0.05) after operation. Stress-induced perfusion defects involved 40% +/- 19% of the left ventricle circumference after stress and showed a significant reduction of size to 23% +/- 14% (p < 0.01) at rest, 4 hours later, and after reinjection. This value fell to 16% +/- 12% (p < 0.05) 3 months after aortocoronary bypass surgery. We conclude that both dobutamine echocardiography (sensitivity 95%, specificity 80%, positive predictive value 87%, negative predictive value 88%) and 201Tl studies (sensitivity 87%, specificity 98%, positive predictive value 97%, negative predictive value 93%) are suitable and comparable accurate methods for predicting improvement in systolic function 3 months after revascularization in a selected population with a high prevalence of viable but hypokinetic or akinetic myocardium.     

Evaluation of patients with diabetes mellitus for coronary artery disease using dobutamine stress echocardiography

BACKGROUND: There is a high prevalence of coronary artery disease (CAD) in patients with diabetes mellitus. Detection of inducible ischaemia using treadmill exercise testing may be limited by the relatively poor inherent predictive accuracy of the test. The purpose of this study was to determine the value of dobutamine stress echocardiography (DSE) for the detection of CAD in patients with diabetes mellitus. METHODS: Patients with diabetes mellitus referred for cardiac assessment were considered eligible for study. DSE was performed in a standard fashion. Significant CAD was defined as a > 50% luminal diameter stenosis on coronary angiography. RESULTS: A total of 52 patients (mean age 59 years) with diabetes mellitus were studied prospectively using DSE. Risk factors for CAD included hypertension in 19, family history in 21, hypercholesterolaemia in 14, history of smoking in 38. The sensitivity, specificity, positive and negative predictive values of DSE for detection of CAD were 82, 54, 84 and 50% respectively. CONCLUSION: The specificity of DSE for CAD in patients with diabetes mellitus is low. Whether this reflects an underdetection of small vessel disease by contrast coronary angiography or whether it relates to test performance is unclear.     

Detection of myocardial viability by echocardiography with dobutamine infusion three weeks after myocardial infarction

The aim of this study was to assess the value of low dose dobutamine (5 and 10 gammas/Kg/min) echocardiography for the detection of hibernating myocardium in an infarcted zone three weeks after the initial infarction. The authors studied 23 patients (18 men, 15 women) with an average age of 59 +/- 8 years before and 3 months after angioplasty of the culprit artery. Segmental wall motion was assessed semi-quantitatively by the criteria of the American Society of Echocardiography. All patients had regional contractile abnormalities under basal conditions and all underwent control coronary angiography at 3 months. Improvement of segmental wall motion with dobutamine predicted improvement after revascularisation with positive and negative predictive values of 95% and 85% respectively. The sensitivity and specificity of the test calculated in the usual manner were 83% and 96% respectively. In addition, assessment of diastolic function showed reduction of the isovolumic relaxation time with dobutamine only in patients with hibernating myocardium (120 +/- 30 ms decreasing to 114 +/- 29 ms with dobutamine, p < 0.02). Low dose dobutamine echocardiography therefore allows reliable non-invasive prediction of hibernating myocardium three weeks after infarction. The reduction of isovolumic relaxation time with dobutamine could be an additional argument in favour of the diagnosis.     

Regional wall motion changes with dobutamine as a pharmacological stress test during cardiac catheterization in patients with significant coronary artery disease

BACKGROUND: Preliminary study to test the feasibility of pharmacological stress testing during cardiac catheterization, thus combining anatomical and functional information. PATIENTS AND METHODS: 21 consecutive patients with known or suspected coronary artery disease, referred for diagnostic catheterization. Biplane ventriculography was performed before and during dobutamine infusion. The patients were subdivided into 3 groups: Group I (n = 11, 52%) with at least one territory supplied by a significantly stenosed coronary artery and showing normal resting regional wall motion. Group II (n = 6, 29%) patients in whom the affected vessel(s) supplied exclusively a territory with regional wall motion abnormalities at rest. Group III (n = 4, 19%) had no significant coronary artery disease and served as control. RESULTS: In group I, 9/11 (82%) patients and in group II, 3/6 (50%) patients showed either ischemia or viability reactions or both after dobutamine stress. Overall, substantial functional information was gathered in 12/17 patients (71%). Control patients showed no worsening of regional wall motion under dobutamine. Neither global left ventricular ejection fraction nor left ventricular end diastolic pressure were as accurate in detecting ischemia as regional wall motion analysis. In patients who had only ischemia and no viability reaction as judged by regional wall motion analysis, ejection fraction fell significantly in 4/6 (67%) patients; end diastolic pressure on the other hand rose significantly in 3/6 (50%). CONCLUSIONS: Dobutamine stress testing performed during cardiac catheterization is convenient, feasible and safe and yields clinically useful information in a high percentage (71%) of patients with significant coronary artery disease. Further experience is needed to evaluate the sensitivity, specificity and predictive value of this new approach.     

Noninvasive diagnosis of coronary artery stenosis in women with limited exercise capacity: comparison of dobutamine stress echocardiography and 99mTc sestamibi single-photon emission CT

OBJECTIVES: To compare the accuracy of dobutamine stress echocardiography (DSE) and simultaneous 99mTc sestamibi (MIBI) single-photon emission CT (SPECT) imaging for the diagnosis of coronary artery stenosis in women. PATIENTS: Seventy women with limited exercise capacity referred for evaluation of myocardial ischemia. METHODS: DSE (up to 40 microg/kg/min) was performed in conjunction with stress MIBI SPECT. Resting MIBI images were acquired 24 h after the stress test. Ischemia was defined as new or worsened wall motion abnormalities confirmed by DSE and as reversible perfusion defects confirmed by MIBI. Significant coronary artery disease was defined as > or = 50% luminal diameter stenosis. RESULTS: DSE was positive for ischemia in 35 of 45 patients with coronary artery stenosis and in 2 of 25 patients without coronary artery stenosis (sensitivity = 78% CI, 68 to 88; specificity = 92% CI, 85 to 99; and accuracy = 83% CI, 74 to 92). A positive MIBI study for ischemia occurred in 29 patients with coronary artery stenosis and in 7 patients without coronary artery stenosis (sensitivity = 64% CI, 53 to 76; specificity = 72% CI, 61 to 83; and accuracy = 67% CI, 56 to 78 [p < 0.05 vs DSE]). In the 59 vascular regions with coronary artery stenosis, the regional sensitivity of DSE was higher than MIBI (69% CI, 62 to 77 vs 51% CI, 42 to 59, p < 0.05), whereas specificity in the 81 vascular regions without significant stenosis was similar (89% CI, 84 to 94 vs 88% CI, 82 to 93, respectively). CONCLUSION: DSE is a useful noninvasive method for the diagnosis of coronary artery stenosis in women and provides a higher overall and regional diagnostic accuracy than dobutamine MIBI SPECT in this particular population.     

Postextrasystolic potentiation and dobutamine echocardiography in predicting recovery of myocardial function after coronary bypass revascularization

BACKGROUND: Identification of viable but hibernating myocardium remains a relevant issue in the current era of myocardial revascularization. Echocardiography can be helpful in detecting reversible contractile dysfunction and optimizing the selection of patients for coronary bypass surgery. METHODS AND RESULTS: Eighty-four consecutive candidates for bypass surgery with chronic multivessel coronary artery disease were screened, and 60 were included in this prospective study. Preoperative evaluation of a reversible contractile dysfunction in asynergic myocardial regions was performed by dobutamine infusion at 5 (low dose) and 10 (intermediate dose) microg x kg(-1) x min(-1) with each stage lasting at least 5 minutes; postextrasystolic potentiation (PESP), with a coupling interval ranging from 500 to 300 ms with a progressive 10-ms decrease; or a combination of both dobutamine infusion and PESP. Sensitivity (92% versus 86%) and predictive accuracy (89% versus 84%) were higher with PESP than dobutamine (P=.009 and P=.001, respectively), but the combination did not improve sensitivity or accuracy. Dobutamine induced ischemic dysfunction in 15% of patients at the intermediate dose; however, the low dose resulted in loss of sensitivity. CONCLUSIONS: PESP echocardiography is a useful and cost-effective method to identify viable myocardium in patients with multivessel coronary disease undergoing revascularization and is more sensitive and accurate than dobutamine infusion.     

Low-dose dobutamine stress echocardiography in children and young adults

Dobutamine stress echocardiography has become widely accepted in the evaluation of adult patients with coronary heart disease. We wanted to assess the feasibility and the physiologic responses of stress echocardiography at low doses of dobutamine in a population of normal children and adults. Once achieved, we submitted a group of post-anthracycline patients to the test to assess the sensitivity of low-dose dobutamine stress echocardiography in the detection of cardiac dysfunction. Thirty-two healthy children and young adults (19 male and 13 female subjects, median age 15 years [range 6 to 26]) were studied. After the initial study of normal subjects, we submitted a cohort of 39 patients (18 female and 21 male, aged 6 to 25 years), who completed anthracycline chemotherapy, to the same protocol. Dobutamine was infused at rates of 0.5 to 2.5 and 5 microg/kg/min and echocardiographic measurements were obtained at rest and at the end of each stage. The test could be completed in 100% of the subjects without major complications. Statistically significant differences between resting echocardiographic values of systolic and diastolic function and values at 2.5 and 5 microg/kg/min of dobutamine were found. Moreover, dobutamine revealed or enhanced differences between normal subjects and the post-anthracycline patients. Thus, low-dose dobutamine stress echocardiography is feasible and safe in older children. The test is very sensitive for the detection of subclinical cardiac dysfunction in post-anthracycline patients and could possibly assess functional myocardial reserve.     

Prospective countywide evaluation of the effects of motor vehicle safety device use on hospital resource use and injury severity

Stress echocardiography is increasingly used for the assessment of coronary artery disease and is valuable in the treatment of patients with known disease as well. Although several studies are available on the accuracy of stress echocardiography in the detection of coronary artery disease and evaluation of its severity, studies on the use of this technique for evaluation of prognosis are just now emerging. Over the past decade, few studies have investigated its prognostic value in different patient populations. The versatility and advantage of stress echocardiography lie in the fact that it provides information on both resting ventricular function and stress-induced ischemia, two important determinants of cardiac events. Exercise echocardiography with the bicycle or posttreadmill approach is used in subjects who can exercise and provides important additional prognostic data from physiologic exercise variables. In patients unable to exercise, pharmacologic stress echocardiography with dobutamine or vasodilators is used. Stress echocardiography has been shown to identify different populations of patients at risk of cardiac events, including those with stable or suspected coronary artery disease, those with acute myocardial infarction, and those scheduled for major noncardiac surgery. In the early postinfarct setting, exercise and vasodilator stress have been used more often, whereas dobutamine echocardiography has been used predominantly at low doses for the assessment of residual myocardial viability. This review focuses on recently published investigations evaluating the prognostic effect of stress echocardiography in patients with stable coronary artery disease or acute myocardial infarction.     

Diagnostic accuracy of dobutamine-atropine stress echocardiography

PURPOSE: To analyze the diagnostic accuracy of dobutamine-atropine stress echocardiography. METHODS: We studied 304 consecutive patients using dobutamine-atropine stress echocardiography who underwent coronary angiography within a month of the exam. Patients received high dobutamine doses associated or not with atropine. RESULTS: The global sensitivity was 92%, specificity was 72% and diagnostic accuracy was 87%. Analyzing 120 patients with normal LV function, we found sensitivity of 85%, specificity of 79% and accuracy of 82%. CONCLUSION: Dobutamine-atropine stress echocardiography is an accurate method for the detection of coronary artery disease.     

Outpatient echocardiography as a predictor of perioperative cardiac morbidity after peripheral vascular surgical procedures

PURPOSE: A variety of preoperative provocative tests have been used to define the risk of cardiac morbidity and mortality after peripheral vascular procedures, including dipyridamole myocardial scintigraphy and dobutamine stress echocardiography. Although highly sensitive, these tests are time-consuming and associated with significant expense. We investigated outpatient echocardiography as a less resource-intensive means of assessing cardiac risk with operation. METHODS: Over a 2-year period 250 consecutive patients underwent outpatient transthoracic echocardiography before elective peripheral vascular operation was performed. The accuracy of the Goldman, Detsky, and the American Society of Anesthesiologists' Physical Status Classification clinical indexes of cardiac risk were assessed with regard to the development of cardiac complications such as unstable angina, myocardial infarction, life-threatening ventricular arrhythmias, severe congestive heart failure, and cardiogenic shock. The accuracy of echocardiographically determined left ventricular ejection fraction was determined at threshold values between 20% and 60%. RESULTS: Perioperative cardiac events developed in 23 (9.2%) of the patients, and nine (3.6%) of the patients died as a result of these complications. Clinical indexes lacked sensitivity in the preoperative prediction of cardiac complications. Receiver operating curve analysis defined a left ventricular ejection fraction of less than 50% as an appropriate threshold for defining patients at high risk, with a sensitivity of 78% and a specificity of 81% in the identification of patients who had cardiac morbidity. The positive predictive value was 27%, and the negative predictive value was 97%. The economic impact of outpatient echocardiography was well below that of dipyridamole myocardial scintigraphy or dobutamine stress echocardiography. CONCLUSIONS: Outpatient echocardiography appears to offer a cost-efficient compromise between clinical criteria alone and provocative cardiac testing such as dipyridamole myocardial scintigraphy and dobutamine stress echocardiography in the preoperative screening of patients undergoing peripheral vascular surgical procedures.     

Effects of beta-blockade and atropine on ischemic responses in left ventricular regions subtending coronary stenosis during dobutamine stress echocardiography

OBJECTIVES: This study was designed to examine the effects of a beta-adrenergic blocking agent on the ischemic response to dobutamine stress and to determine the degree to which these effects can be abolished by the addition of atropine. BACKGROUND: Whether beta-blockade affects the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease has been controversial. METHODS: In nine pigs, a left anterior descending coronary artery stenosis was created to reduce flow reserve (maximal/rest flow) to 1.1 to 1.9 without baseline regional wall motion abnormalities. This corresponded to a 50% to 90% diameter stenosis. Wall thickening was measured using epicardial echocardiography. Regional lactate production and coronary venous pH were monitored from an adjacent cardiac vein. A standard protocol of dobutamine stress echocardiography was first performed. After normalization of the ischemic abnormalities elicited with this infusion, esmolol was infused at 50 micrograms/kg body weight per min and the dobutamine test was repeated, with 1.0 mg of atropine added at the maximal dobutamine dose. RESULTS: Without esmolol, dobutamine stress induced myocardial ischemia with a reduction in regional wall thickening and lactate production in all nine pigs. Multiple regression analysis revealed that coronary flow per heartbeat (p < 0.01) and lactate production (p < 0.05) independently correlated with regional wall thickening during dobutamine stress. The beta-blocker significantly reduced heart rate and regional oxygen consumption and altered the relation between coronary flow per heartbeat and regional wall thickening (p < 0.05) during dobutamine stress. Esmolol prevented dobutamine-induced ischemia (lactate production and wall motion abnormalities) in seven of nine pigs. The addition of atropine induced lactate production and a reduction in wall thickening in five of seven pigs in which ischemia had been prevented by beta-blockade. However, lactate production was higher and regional venous pH was lower with the baseline dobutamine infusion than with that performed after esmolol with atropine added at the maximal dobutamine dose (p < 0.05). CONCLUSIONS: A correlation between regional wall thickening and coronary flow per heartbeat was demonstrated during baseline dobutamine stress. Beta-blockade shifted this relation so that dobutamine stress-induced myocardial ischemia was attenuated. The mechanisms by which beta-blockade prevents dobutamine-induced ischemia appeared to be mainly through decreases in heart rate and rate of rise in left ventricular pressure, improvement of regional coronary flow per heartbeat and attenuation of regional ischemic lactate production. Adding atropine in conventional doses enhanced the ability of dobutamine stress to induce myocardial ischemia but did not completely abolish the effects of beta-blockade on either the severity of dobutamine-induced wall thickening abnormalities or regional metabolic disturbances.